In the prior art devices, conventional diffusers have required supersonic throat lengths of 6 to 10 times the inlet height of the supersonic gas flow for Mach numbers of interest in chemical lasers. Also, there is a need for a minimum length diffuser in chemical lasers which characteristically operates at very low static pressures with gas outlet total temperatures of about 1500 to 2000 degrees Kelvin. Laser exhaust gases typically have a Mach number of approximately 2 with a total pressure of approximately 30 to 60 torr. The gas is normally diffused through conventional techniques to a high pressure subsonic flow condition in which a reactive chemical bed converts the gas to solid products having very low vapor pressures. The low pressure laser operating regime is conducive to very high laser efficiency, but these prior art devices require a large cross-sectional gas flow area to achieve large mass flow and thus high laser power. Practical constraints usually dictate a maximum laser gain length. The laser device power can only be increased by increasing the height of the gas cross-sectional flow area. Conventional diffusers which increase in length by fixed proportions to gas cross-sectional height become very large, heavy, and costly, eventually limiting laser power which can be generated within prescribed volume and weight limits. Therefore, there is a need for a diffuser that has reduced volume to accomplish improved pressure recovery performance, reduced weight, and reduced cost.
Therefore, it is an object of this invention to provide a minimum length diffuser which is essentially independent of cross-sectional height of the flow area.
Another object of this invention is to provide a diffuser which requires approximately one-sixth to one-tenth the volume of a conventional diffuser for laser bank heights of 6 to 10 inches.
Still another object of this invention is to provide a diffuser that has reduced volume accompanied by improved pressure recovery performance, reduced weight, and reduced cost.
Still another object of this invention is to provide a diffuser which can effectively be used to increase the laser power and can be packaged in a restricted weight or volume situation.
Other objects and advantages of this invention will be obvious to those skilled in this art.